Conveyance device

The present disclosure relates to a conveyance device.

With the advancement of medical care and aging of society, the importance of specimen processing in a clinical test is increasing.

A specimen processing device used in a clinical test tests a predetermined analysis item on a biological sample (a specimen) of a body fluid or the like such as blood, plasma, serum, and urine. The specimen processing device can connect devices having a plurality of functions and automatically process each step. In other words, in order to rationalize work in an inspection room, analysis units in a plurality of analysis fields such as biochemistry and immunity are connected by a conveyance line and are operated as one device.

A conveyance line in the related art is mainly of a belt drive type. Therefore, when conveyance is stopped due to an abnormality occurring in the middle of the conveyance, a specimen cannot be supplied to a downstream device.

In order to improve a processing capacity of a specimen processing device, it is desired to convey specimens at high speed, convey a large number of specimens at the same time, and convey specimens in a plurality of directions.

PTL 1 discloses an electromagnetic actuator that is a container carrier including a magnetic active device such as a permanent magnet, that is disposed to be stationary below a conveyance plane adapted to carry a container adapted to carry a sample container, and that is adapted to move the container carrier on the conveyance plane by applying a magnetic force to the container carrier. Further, PTL 1 discloses that a speed of the container carrier that is moved on the conveyance plane is set by setting a time between contiguous activation of adjacent electromagnetic actuators. Further, PTL 1 discloses that a container carrier detection device embodied based on a reflected light barrier mainly including an infrared ray (IR) is provided in order to detect a presence and position of the container carrier positioned on the conveyance plane.

PTL 2 discloses a configuration in which each of a plurality of electromagnetic actuators used in a laboratory sample distribution system includes a ferromagnetic core and an excitation winding wire, and the excitation winding wire exceeds the assigned ferromagnetic core in a vertical direction. In addition, PTL 2 discloses that the plurality of electromagnetic actuators are disposed below a transfer surface of the laboratory sample distribution system, and a plurality of position sensors embodied as Hall sensors are distributed on the transfer surface.

Further, PTL 3 discloses a conveyance device including a first magnetic body provided on a conveyance body side, a magnetic circuit including a core made of a second magnetic body and a winding wire wound around an outer peripheral side of the core, a driving circuit for supplying a current to the winding wire of the magnetic circuit, and a conveyance body detection unit for detecting a position or a speed of the magnetic body. The current supplied to the winding wire is changed based on the position or the speed information of the magnetic body detected by the conveyance body detection unit.

PTL 4 discloses a conveyance device in which a coil driving unit that applies a voltage to each of a plurality of coils applies a driving current to a predetermined coil based on a position of a conveyance object estimated by a position estimation unit and path information stored in a path information storage unit, and applies a current for position detection to a closest coil estimated to be closest to the conveyance object and coils around the closest coil. Further, PTL 4 discloses that a current change amount for each position is calculated based on an inductance characteristic, a position of a permanent magnet is estimated at any time by sequentially calculating the current change amount, it is determined whether a conveyance object deviates from a predetermined path, and a pulse voltage is output to the predetermined coil so as to return to the predetermined path.

A large number of sensors (position sensors) for detecting the positions of the container carrier detection device in PTL 1 and the Hall sensors in PTL 2 are required, and there is a concern that a cost is increased and reliability is lowered due to a failure of the position sensor. Further, in PTLS 1 and 2, since the presence or absence of the conveyance object cannot be detected unless the conveyance object approaches the position sensor to some extent, it is considered that it is difficult to detect the conveyance object in all regions on the conveyance surface.

In PTL 3, the current flowing through the winding wire is changed according to the position, weight, and the like of the conveyance object, but a method of determining a value of a current in a section in which the detection of the position and the like is difficult is unknown. Therefore, it is conceivable that variations in speed occur among the conveyance objects.

In PTL 4, although the deviation of the conveyance object is corrected, adjustment of the speed of the conveyance object is unclear.

An object of the present disclosure is to implement, in a conveyance device that has a function of estimating a position of a conveyance object based on information on a current flowing through winding wires of coils, stable conveyance speed control even in a section in which accuracy for estimating a position or speed of the conveyance object is low.

A conveyance device according to the present disclosure conveys a conveyance object having a magnetic body, the conveyance device including: a plurality of coils configured to generate magnetic flux acting on the magnetic body; a coil driving unit configured to apply a voltage to each of the plurality of coils; and a calculation control unit including a current control unit and a position estimation unit. The current control unit determines the voltage. The position estimation unit estimates a position of the conveyance object based on a change in a current generated by applying a voltage pulse to the coils and switches, according to a position estimation value that indicates the position of the conveyance object estimated by the position estimation unit, between a speed control mode in which a speed of the conveyance object is controlled and a current control mode in which a current through the coils is controlled.

According to the present disclosure, in the conveyance device that has a function of estimating the position of the conveyance object based on information on the current flowing through winding wires of the coils, it is possible to implement stable conveyance speed control even in a section in which accuracy for estimating the position or speed of the conveyance object is low.

The present disclosure relates to a specimen analysis system that analyzes a biological sample (hereinafter, referred to as a “specimen”) such as blood and urine, and a conveyance device suitable for a specimen preprocessing device that performs preprocessing necessary for an analysis.

Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

is a schematic configuration diagram showing a conveyance device according to an embodiment.

In the drawing, a conveyance deviceincludes a permanent magnet, two coils, coil driving units(driving circuits), a power supply, a current detector, and a calculation unit(calculation control unit). The permanent magnetis provided in a specimen folder or the like which is a conveyance object. The coilincludes a cylindrical coreand a winding wireprovided on an outer peripheral side of the core. Although two coilsare shown in the drawing, two or more coilsare usually provided.

The coil driving unitsare connected to the coils, respectively. The current detectordetects a current flowing from each coil driving unitto the winding wireof each coil.

A propulsive force is generated in the permanent magnetby an interaction with the coil. A conveyance object such as the specimen folder provided with the permanent magnetis moved when the conveyance object receives the propulsive force. Accordingly, a specimen container or the like (not shown) provided in the specimen folder is conveyed. A speed, a movement direction, a destination, and the like of the conveyance object are adjusted by controlling a current flowing through the coil.

In general, a conveyance surface (not shown) for supporting the permanent magnetis provided between the coiland the permanent magnet. A plurality of coilsmay be provided in a row below the conveyance surface. In this case, the conveyance surface may be a surface on which the conveyance object is moved along a linear or curved path. When the conveyance surface is an xy plane, a plurality of coilsmay be provided below the xy plane in rows in each of an x axis direction and a y axis direction. The permanent magnetis moved in a manner of sliding on the conveyance surface. A container to be conveyed is not limited to the specimen container, and may be a reagent container or the like. Therefore, the container to be conveyed may be referred to as a “conveyance container”. In addition, the conveyance object includes a small conveyable device.

The conveyance devicemoves the conveyance object between the coilsby applying a current to the winding wireand applying an electromagnetic force to the permanent magnet. In order to efficiently apply the electromagnetic force and move the conveyance object in a desired direction, relative position information between the permanent magnetand the coilis required.

For example, when the permanent magnetis located directly above one of the two coils, no force in a conveyance direction is generated even when a current flows through the coildirectly below the permanent magnet. On the other hand, when a current flows through the coiladjacent to the coildirectly below the permanent magnet, a force for attracting the permanent magnetto the adjacent coilcan be generated. That is, a force can be efficiently generated and a direction of the force can be controlled.

By adopting a configuration in which three or more coilsare disposed side by side and sequentially switching the coilsto be energized (energized coils), it is possible to freely move the conveyance object provided with the permanent magnet.

In the present embodiment, a method based on inductance characteristics of the coilis used to detect a position of the permanent magneton the conveyance surface. This point is different from a method of detecting a position of the conveyance object by arranging a large number of position sensors on the conveyance surface as in the technique of the related art.

When a large number of position sensors are used as in the related art, position information can be obtained, but a substrate or the like on which a position sensor is newly mounted is required, which causes a problem of an increase in cost and an increase in size of the device.

Hereinafter, a position detection method according to the embodiment will be described.

When the permanent magnetis located above the front-side coilshown in, magnetic flux generated by the permanent magnetacts on the coil. A magnitude of the acting magnetic flux is different between the front-side coiland a back-side coil. In other words, the magnitude of the magnetic flux acting on the coilchanges depending on a relative position relationship between the permanent magnetand the coil.

When a voltage is applied to the winding wireby the coil driving unitto cause a current to flow through the winding wire, magnetic flux generated by the current is generated in the core. Therefore, in the core, the magnetic flux generated by the permanent magnetand the magnetic flux generated by the current flowing through the winding wireoverlap each other.

In general, when a current flows through the winding wire, a magnetic field is generated around the winding wire. At this time, the generated magnetic flux is proportional to a value of the flowing current. This proportional constant is called an inductance.

However, in a circuit including a magnetic body such as the core, the inductance changes due to magnetic saturation characteristics of the core. That is, the inductance of the winding wirechanges depending on the magnitude of the magnetic flux of the permanent magnet. This refers to that the inductance of the winding wirechanges depending on the position of the permanent magnet(that is, conveyance object).

Therefore, if the inductance of the winding wirecan be measured, the position of the permanent magneton the conveyance surface can be detected.

The above is a principle of the position detection method based on the inductance characteristics of the coil.

Next, the more specific principle of the position detection method will be described.

A voltage V generated in the winding wireis expressed by the following Formula (1). That is, the voltage V is a change amount of the magnetic flux per unit time.

In this Formula, φ is the magnetic flux, and t is a time.

When a current is I and the inductance is L, the following relational Formula (2) is established.

The following relational Formula (3) is obtained from the above Formulas (1) and (2).

That is, when a constant voltage is applied to the winding wire, a time derivative of the supplied current I changes depending on a magnitude of the inductance L as shown in the above Formula (3). This refers to that when a voltage is applied, a manner of rising the supplied current is different.

Accordingly, the inductance L can be calculated and obtained by detecting a change amount (dI/dt) in the current generated in the winding wirewhen a voltage is applied to the winding wire. That is, if characteristics of the inductance L of the winding wirethat change depending on the position of the permanent magnetcan be grasped in advance, the position of the permanent magnet, that is, the conveyance object is obtained by applying a voltage signal for position detection and detecting the change amount (dI/dt) in the current generated by applying the voltage signal.

Next, a position detection method without the position sensor according to the embodiment will be further described.

As shown in, a voltage is applied to the winding wireby the coil driving unit, and a coil current flowing by the voltage is detected by the current detector. Here, the coil driving unitcorresponds to, for example, a bidirectional chopper driven by a pulse width modulation (PWM) signal. The current detectorfor detecting a current may be a current detector using a shunt resistor or a current transformer, or a current detector using a Hall current sensor, and the present embodiment is not particularly limited thereto.

The coil driving unitis connected to the power supply, and a predetermined current flows through the winding wireof the coilby performing duty control on a power supply voltage.

Further, the calculation unitcalculates a voltage command value to be applied to the coil driving unitin order to obtain a propulsive force necessary for conveying the conveyance object, measures a current change rate dI/dt generated in the coilbased on a current value detected by the current detector, calculates the relative positional relationship between the coiland the permanent magnet, and estimates the position of the permanent magnetin the conveyance device. The calculation unituses the estimated position information of the permanent magnetto determine a timing at which a current necessary for conveying the permanent magnet(conveyance object) is supplied from the coil driving unit, and causes the current to flow through the actually appropriate coil.

is a block diagram showing a configuration of the calculation unit shown in.